Active displays using packaged inorganic LEDs as blue, red, and green pixels are well known and are commonly used for large displays due to the relatively large pixels composed of standard size packaged LEDs. A conventional LED die is about 0.1-1 mm2, and a packaged LED is typically a few millimeters in diameter and includes a lens for improving light extraction. Such displays are relatively thick and rigid since they use printed circuit boards. Using such a design for a small display is not particularly useful due to the low pixel density, the thickness, and the relatively high expense.
Organic LED (OLED) displays can be made very flat with a high pixel density, but such OLEDs generally have poor reliability and a short lifetime.
What is needed is a display that uses long-life inorganic LEDs, where the display may be made very thin and inexpensively, and where the pixels may have a high density.